Conversion of continuous filaments



W. POOL Oct. 29, 1940.

CONVERSION OF CONTINUOUS FILAMENTS INTO STAPLE FIBERS Original FiledJuly 27, 1937 W POOL.

Patented Oct. 29, 1940 UNITED STATES CONVERSION or ooN'rmuoUs FILAMENTSm'ro STAPLE mans William Pool, Spondon, near Derby, England, as-

signorto Celanese Corporation of America, a corporation of DelawareApplication July 27, 1937, Serial No. 155,949. Re-

newed November 14, July 31, 1936 11 Claims.

The invention relates to the conversion of continuous filaments intostaple fibers and more particularly to the cutting of continuousfilaments into staple fibers of predetermined length.

According to the invention a bundle of substantially twistlesscontinuous filaments is converted into staple fibers by apparatus whichcomprises means for feeding forward the bundle, means for separating thefilaments of the bundle from each other at the end of the bundle, acutting device comprising a pair of multi-toothed co-operating membersof a width sufficient to accommodate the separated filaments, and meansfor operating the cutting device at intervals so as to cut from theseparated filaments a succession of groups of separated staple fibers ofpredetermined length.

The multi-toothed form of the cutting members provides a large number ofcutting points 20 distributed across the width of the separatedfilaments and so enables the filaments to be converted into acorresponding number or group of fibers while maintaining the fibers inthe separated condition. The cutting device is capable 25 of operatingat high frequency and, moreover,

requires only a slight'cutting pressure to be applied to the filaments,which is of advantage in reducing the tendency of the cut ends of thefibers to stick together, as is found when cellulose acetate filaments,for example, are subjected to heavy cutting pressures.

As the filaments are fed into cutting position they are brought by anysuitable means between the teeth of the cutting members. Con- 3veniently the multi-toothed cutting device is disposed out of the lineof feed of the filaments and the filaments are deflected into the teethafter the requisite length has been fed forward. The cutting device,however, may itself be arranged 49 to move towards the filaments.

The cutting device may be disposed so as to cut the separated filamentsobliquely across the width of the filaments so that the ends of thefibers of a group are progressively staggered lengthwise of the group.Such cutting assists in preserving the separated condition of the fibersand enables the groups to be opened easily and quickly in a subsequentcarding, blending or like operation.

50 Where, with such an obliquely disposed cutter,

the filaments are deflected into the teeth of the cutter the deflectingmeans'a're arranged at an appropriate angle, the deflecting meansconveniently being in the form of two rods disposed so as to move one toeach side of the cutter-to ensure 1939. In Great BritaiL that thefilaments are carried between the teeth of the cutter. I

The bundle of associated continuous filaments to be converted intostaple fibers may take the form of a. band or thread of untwistedfilaments 5 or of a thread having a very low degree of twist, but in thelatter case, the degree of twist should be sufiiciently low to enablethe component filaments to be separated one from the other. Theexpression substantiallytwistless used in connection with the bundlemeans that the bundle contains no twist or that if any twist is presentin the bundle, it should be insufiicient to hinder free separation onefrom the other of the component filaments at the end of the bundle.

The separation of the filaments over the requisite length (i. e. alength longer than the length of staple desired) may be effected as thefilaments are about to be cut into the staple fibers. Thus, the end ofthe bundle may be subjected to the action of a gaseous blast that servesto separate the component filaments of the bundle from each other and,at the same time, feed them to the cutting device. For example, thefilaments may be led through an ejector nozzle pointing towards thecutting device and supplied with compressed air, the filaments beingejected from the nozzle and forwarded to the cutting device in separatedcondition. The action of the gaseous blast serves to remove any smallamount of twist which may be in the bundle. The nozzle may withadvantage be formed with a flat flared ejecting orifice so that thefilaments are separated into a substantially flat band, such separationfacilitating the cutting and assisting in maintaining freedom of thefibers in the cut fiber groups, as will appear hereinafter.

In order to control the separated filaments during cutting, means may beprovided to seize and hold the free ends of the filaments as, forexample, an endless permeable support, in the form of a permeable band,or a drum or wheel having a permeable surface, through which suction isapplied. With such an arrangement the free ends of the filaments aredrawn to and held on the permeable surface by the suction and whilesoheld are cut by the cutting means. After cutting has been effected thesupport may be moved to convey the cut fibers from the position at whichsuction is applied, in readiness for the collecting of the fibers fromthe support. The staple fibers may be collected in separated conditionfor subsequent conversion into yarn with or without blending or mixingwith other fibers, the separated condition of the fibers enabling thefibers to be carded uniformly and formed into a sub-- stantially regularproduct. I

When cutting staple fibers from filaments of material such ascellulos'e'acetate or other organic derivative of cellulose having] ahigh di-electric strength and consequently liable to retain changes ofstatic electricity, it is found that by rubbing the filaments prior toopening them a charge of static electricity is induced '15 Suchpreliminary spreading may be enhanced by limiting the opportunity forthe static charge to leave the filaments prior to being separated, as

by covering with rubber or like electrical insulating material machineparts with which the 20 electrified filaments are likely to contact.

By way of example the invention will now be described in greater detailwith reference to the accompanying diagrammatic drawings of which Fig. lis a part cross-sectional-end elevation of 25 a filament-convertingmachine generally similar to part of that shown in U. S. application S.No. 155,226 filed July 23, 1937;

Fig. 2 shows diagrammatically a succession of fibers produced by theapparatus shown in Fig. 1;

30 Fig. 3 is a detail of Fig. 1 on a larger scale; and

Fig. 4- is a cross-sectional elevation of a detail of Figs. 1 and. 2 ona large scale.

In the following description reference is made only to the salientfeatures of the apparatus, a

35 more detailed description of which may be had from U. S. applicationS. No. 155,226 above mentioned.

Referring to Figs. 1 and 3 a bundle band or thread of substantiallytwistless continuous fila- 0 ments 8 is withdrawn from a supply bobbin 9by a pair of nip rollers III, the filaments passing from the supplybobbin to the rollers by way of guides II and through a-gate tensiondevice I2. The nip rollers I0 feed the filaments to an ejector 45 nozzleI3 formed with a filament entrance hole 30 (Fig. 4) and a flat flaredejecting orifice I4, the nozzle being fed with compressed air from asupply pipe I5.

As indicated by arrows in Fig. 4 the air passes 50 downwardly along aconduit 32 and through a jet 33 to the orifice I4, the jet being formedwith three adjacent passages 34 in order to spread the blast of air asit passes through and out of the orifice I4 the flat flared shape ofwhich assists 5 in flattening and spreading out the current fanwise.

The air blast issuing from the ejecting orifice I4 ejects the filaments8 from the orifice and separates the filaments one from the other in the60 form of a substantially flat band during the ejection. The bandwisespreading of the filaments facilitates their subsequent manipulation aswill appear hereinafter. The bundle of filaments should not contain afinish that prevents the air 65 current from separating the'filaments,and for this reason it is desirable to employ unlubricated filaments.

On being ejected from the orifice I4 the separated filaments 8 extendacross an endless per- 70 meable band I6 which is driven over thesurface of a. suction conduit H by a roller I8 engaging the inside ofthe band. The roller I8 is hollow and is supplied with compressed airwhich discharges from the roller through perforations 75 formed in itsperiphery, the air passing outwardly continuous through the band I6 ina-manner and for a purpose to be described later. The band is kept tautby an idler roller I9 which is spring-urged into contact with the band.The suction conduit. I1 is connected to a suction vessel 20 by a pipe2|. 5 As shown clearly in Figs. 1 and 3 the conduit I1 is of flattenedcross-section and is perforated at two points 22, 23, two'separatestreams of air thus flowing into the conduit through the permeable bandI6 as indicated by the arrows. On the ejec- 10 tion of the filaments 8from the orifice I4 the ends of the separated filaments are attracted toand held on the band I5 by the suction .due to the perforations 22.

Substantially simultaneously with the sucking to the band I6 of thefilament ends a cam 40, of a series of earns 40, 4|, 42 and 43, fixed toa driving shaft 3I (see Fig. 3) is caused by the rotation of the shaftto press the stem 45 of a valve 46 controlling the supply of airto thenozzle I3. The pressing of the stem interrupts the sup- I ply of air tothe nozzle, and the separated filaments are left extending fromtheorifice I4 to r the band I6. g

The succeeding cam 4I (partly-hidden from view by the cam 40) now bearsagainst the end 41 of a deflecting lever 48, and causes the lever torock about its pivot 49. The lever 48 isformed with a forked portion 24which iscaused by the rocking of the lever to bear downwardly upon theseparated filaments 8 extending from the orifice I4 to the band I6 anddeflect the filaments into the teeth of a multi-toothed cutting device25 which is disposed obliquely with respect to the width of theseparated filaments. Onfdefiection, one limb of the forked portion 24lies to each side of the cutting device 25 to ensure proper engagementof the filaments with'the teeth.

.On engagement of the filaments 8 by the teeth of the cutting device 25,the next cam, 42, bears 40 against the end 50 of a lever 5| and causesthe lever to rock about its pivot 52. The lever is connected by anupright arm 53 to the cutting device 25, the rocking of the lever thusoperating the device to cut the filaments. Two or more cutting devices25 may be arranged for operation by common actuating means, and two ormore defleeting levers 48 may likewise be arranged for common actuation.g

The freshly cut end of the fiber-group'thus 50 formed is sucked awayfrom the cutting device 25 and on to theband I6 by the air currentflowing into the conduit through the perforations 23, the air currentbeing inpart concentrated onthe teeth of the cutting device by a shield26 arranged between the cutting device and the perforations 23. A staplelength or group of filaments is thus cut and laid on the surface of themoving band I6. 3

t On operation of the cutting device 25 a pivoted 0 guiding member 2'!normally disposed behind the continuous filaments as they proceed inastraight line from the nip rollers III to the nozzle. I3 is rotatedabout its pivot (viz. to the right as shown in Figs. 1 and 3 by the cam43) and in so moving deflects the filaments from the straight line andoperative position and the air blast. is restarted to separate andeject-the filaments over the "band I5. again from theorifice I4, by thecontinued rotation of earns 43 and 40. The ends of the separatedfilaments are again sucked to the band It in the manner shown in Fig. 1and the sequence of operations described above is repeated.

As shown in Figs. 1 and 3 the lower nip roller I is driven by a chain 35from a chain sprocket 36 attached to the driving shaft 3| which isdriven by chain and sprocket gearing 31 from any suitable source ofpower, while the upper roller is driven by frictional contact with thelower nip roller l0.

The shaft 3| also drives through chain and sprocket gearing 38 a shaft39 upon which is mounted the roller II! which drives the band l6.

While the nip rollers (0 feed the continuous filaments 8 to the nozzlel3 continuously, and the filaments are ejected from the nozzle to theband it intermittently, the ejecting and cutting operations are efiectedin such rapid succession than any small amount of slack formed in thefilaments between the rollers and the nozzle due to the continued feedof the filaments during the periods in which the compressed air supplyis stopped is insignificant and is quickly taken up by the air blastwhen the air supply is restarted. The nip rollers may, however, bedriven intermittently in accordance with the timing of the air blasts. 1

The rate of progress of the filaments 8 from the orifice I4 is dependenton the rate of rotation of the nip rollers l0 and by adjusting suchrota- .tion the staple length of the fibers laid on the band l6 can beregulated. With the continuous filaments delivered at a constant rate toa cutting device working with a constant frequency the fibers aresubstantially uniform in length.

Each successive group of fibers cut from the end of the filament bundleremains held to the band I6, the groups being carried away from thecutting device by the movement of the band Depending on the relativerates of feeding the filaments and of moving the band, the groups may beseparate from each other on the band, or may overlap each other, asshown in Fig. 2.

As the band I6 travels along its course the fiber groups drop away fromthe band into a suitable container (not shown) disposed beneath theband. The removal of the groups of fibers from the band is assisted bythe currents of air escaping through the perforations formed in thehollow roller l8 and passing outwardly through the band.

As shown in Figs. 1 and 3 the cutting device 25 is disposed obliquelywith respect to the width of the filaments so that the cut ends of thefilaments are progressively staggered lengthwise of the bunch. Sucharrangement is of advantage in that the separated condition of thestaple fibers is preserved and the groups are capable of being openedeasily and quickly in a subsequent carding, blending or like operation.

While apparatus for the treatment of one bundle of continuous filaments8 only has been referred to in the foregoing description, it will beunderstood that any number of such forms of apparatus could be disposedin .side-by-side relation in order simultaneously to treat any desirednumber of bundles.

When forming staple fibers from continuous filaments of material such ascellulose acetate or other organic derivative of cellulose having 'a'.high di-electric strength and consequently liable to retain charges ofstatic electricity, it is found that the gate tensioning device 12 inaddition 75 to subjecting the filaments to the desired tension length.

electrifies the filaments and thus causes them to repel each other withthe result that the filaments are given a desirable preliminaryspreading prior to entering the ejector nozzle l3. Such preliminaryspreading may be enhanced by limiting the opportunity for the staticcharge to leave the filaments prior to entering the nozzle, and for thisreason at least the upper nip roller l0 may with advantage be coveredwith rubber or other electrical insulating material. In order to preventexcessive wear on any one portion of the nip rollers In the filaments 8may be traversed to and fro along the length of the rollers.

Having described my invention, what I desire to secure by Letters Patentis:

. 1. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, means for separating the filaments of the bundle from eachother at the end of the bundle, at cutting device comprising a pair ofmulti-toothed co-operating members of a width sufficient to accommodatethe separated filaments, and means for operating the cutting device atintervals so as to out from the separated filaments a succession ofgroups of separated staple fibers of predetermined length.

2. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, means for separating the filaments of the bundle from eachother at the end of the bundle, a cutting device comprising a pair ofmulti-toothed co-operating members of a width sufficient to accommodatethe separated filaments, said cutting device being disposed near thepath of the separated filaments, means for bringing the separatedfilaments and the cutting device into engagement with each other atintervals, and means for operating the cutting device during suchengagement so as to cut from the separated filaments a succession ofgroups of separated staple fibers of predetermined 3. Apparatus for themanufacture of staple fibers from continuous filaments, comprising meansfor feeding forward a bundle of continuous filaments, an ejector nozzleadapted to receive the end of the bundle and to apply thereto a gaseousblast so as both to separate the fila ments at the end of the bundlefrom each other and to forward the filaments, a cutting devicecomprising a pair of multi-toothed co-operating the filaments at the endof the bundle into the form of a flat band and to forward the filaments,a cutting device comprising a pair of multitoothed co-operating membersof a width sufi1-' cient to accommodate the separated filaments, andmeans for operating the cutting device at intervals so as to cut fromthe separated filaments a succession of groups of separated staplefibers of predetermined length.

filaments, an ejector nozzle adapted to receive the end of the bundleand to apply thereto a gaseous blast so as both to separate thefilaments at the end of the bundle from each other and to forward thefilaments, a cutting device comprising a pair of multi-toothedco-operating members of a width sufiicient to accommodate the separatedfilaments, said cutting device being disposed near the path of the blastproduced by the nozzle, means for bringing the separated filaments intoengagement with the cutting device at intervals, and means for operatingthe cutting device during such engagement so as to cut from theseparated filaments a succession of groups of separated staple fibers ofpredetermined length.

6. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, means for separating the filaments of the bundle from eachother at the end of the bundle, a cutting device comprising a pair ofmulti-toothed co-operating members of a width sufficient to accommodatethe separated filaments, said cutting device being disposed near thepath of the separated filaments, means for bringing the separatedfilaments into engagement H with the, cutting device at intervals, meansfor operating the cutting device during such engagement so as to cutfrom the separated filaments a succession of groups of separated staplefibers of predetermined length, and means for drawing the ends of theseparated filaments clear of the cutting device after each cuttingoperation. I

7. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, an ejector nozzle formed with a fiat, flared ejectingorifice, said nozzle being adapted to receive the end of the bundle andto apply thereto a gaseous blast so as both to separate the filaments atthe end of the bundle'into the form of a fiat band and to forward thefilaments, a cutting device comprising a pair of multitoothedco-operating members of a width sulficient .to accommodate the separatedfilaments, said cutting device being disposed near the path of theseparated filamentsimeans for operating the cutting device at intervalsso as to cut from the separated filaments a succession of groups ofseparated staple fibers of predetermined length, and means for drawingthe ends of the separated filaments clear of the cutting device aftereach cutting operation.

8. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, means for separating the filaments of the bundle from eachother atthe end of the bundle, a cutting device comprising a pair ofmulti-toothed co-operating members of a width sufiicient to accommodatethe separated filaments,

said co-operating members being disposed obliquely across the width ofthe separated filaments, and means for operating the cutting device atintervals so as to cut from the separated filaments a succession ofgroups of separated staple fibers of predetermined length, the ends ofeach fiber of a group being staggered with respect to the ends of theother fibers of the group.

9. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, a nozzle disposed in the path of the bundle, said nozzlebeing formed with an orifice adaptedto receive the end of the bundle anda further orifice adapted for the ejection of the bundle, means forsupplying the ejecting orifice with compressed air so that the filamentsat the endof the bundle received in the receiving orifice are ejectedfrom the ejecting orifice and during such ejection are separated onefrom the other,

I means for interrupting the compressed air supply -multi-toothedco-operating members of a width sufiicient to accommodate the separatedfilaments, said cutting device being disposed near the path of the airblast produced by the nozzle, means for bringing the separated filamentsinto engagement with'the cutting device between the ejecting intervals,and means for operating the cutting device during such engagement so asto cut from the separated filaments a succession of groups of separatedstaple fibers of predetermined length. a

10. Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, means for separating the filaments of the bundle from eachother at the end of the bundle, a cutting device comprising a pair ofmulti-toothed co-operating members of a'width sufiicient to accommodatethe separated filaments, means for operating the cutting device atintervals so as to cut from the separated filaments a succession ofgroups of separated staple fibers of predetermined length, and a movablesupport disposed near the cutting device and adapted to carry thesuccession of groups of fibers awa from the cutting device.

11, Apparatus for the manufacture of staple fibers from continuousfilaments, comprising means for feeding forward a bundle of continuousfilaments, a gate tension device disposed in the path of the filamentsso as to impart tension to the filaments prior to their engagement withthe feeding means, means for separating the filaments of the bundle fromeach other at the end ofthe bundle, a cutting device comprising a pairof multi-toothed co-operating members of a width sufiicient toaccommodate the separated filaments, and means for operating the cuttingdevice at intervals so as to cut from the separated filaments asuccession of groups of separated staple fibers of predetermined length.

WILLIAM POOL.

